December 4, 2013

Early Warning System Needed In A World With Changing Climates

The National Research Council says that even gradual climate change can have abrupt impacts in human infrastructure and ecosystems if critical thresholds are crossed, so an early warning system needs to be developed now, before its too late.

The federal report calls for the development of an early warning system that could help anticipate sudden changes and emerging impacts.

"Research has helped us begin to distinguish more imminent threats from those that are less likely to happen this century," stated James W.C. White, professor of geological sciences at the University of Colorado, Boulder, and chair of the committee that wrote the report. "Evaluating climate changes and impacts in terms of their potential magnitude and the likelihood they will occur will help policymakers and communities make informed decisions about how to prepare for or adapt to them."

According to the report, abrupt climate changes and impacts already under way are of immediate concern, including the disappearance of late-summer Arctic sea ice and increase in extinction rates of marine and terrestrial species.

“The phrase ‘Here be dragons’ appears on one of the first known globes produced in Europe following Christopher Columbus’ voyage across the Atlantic Ocean. That globe shows some of the vast uncertainties that Columbus’ exploration highlighted for Europe — indeed, North America is portrayed as just a few islands,” the authors wrote in the journal The National Academic Press. “By analogy, many investigations into the climate and Earth system have revealed possible dangers. Some of those have been confirmed or even amplified, such as the impacts of chlorofluorocarbons on the ozone layer that were understood in the 1970s before the Antarctic Ozone Hole was discovered the following decade.”

“In looking back at the previous studies of abrupt climate change in the introduction of this report, the committee notes that even when dragons are identified and clearly pointed out, they still may then be ignored and their presence not acted upon.”

The team said that ignoring early warnings is a well-documented phenomenon in environmental research and that scientists have learned some major lessons from this scenario.

Scientific understanding of climate change has progressed enough to determine whether certain high-impact climate changes could happen within the next century. The researchers say that a shutdown in the Atlantic Ocean circulation patterns or a rapid release of methane from high-latitude permafrost or undersea ice are now known to be unlikely to happen during this century.

The report says that changes in the physical climate system that happen gradually over many decades or centuries can cause abrupt ecological or socio-economic changes once a “tipping point” is reached. Relatively slow global sea-level rise could affect local infrastructures like roads, airports, pipelines, or subway systems. Slight increases in ocean acidity or surface temperatures could cross thresholds beyond which many species cannot survive.

The authors wrote that further scientific research and enhanced monitoring of the climate, ecosystems and social systems may be able to provide information that a tipping point is imminent, which could allow time for adaption or possibly mitigation.

"Right now we don’t know what many of these thresholds are," White said. "But with better information, we will be able to anticipate some major changes before they occur and help reduce the potential consequences."

There are still some areas of research that need focus, including identifying keystone species whose population decline, due to an abrupt change, would have cascading effects on ecosystems.

The authors wrote that an effective early warning system would need to include careful and vigilant monitoring, taking advantage of existing land and satellite systems and modifying them if necessary. The system would also need to be flexible and adaptive, regularly conducting and alternating between data collection, model testing and improvement.